Circularly polarized x rays from a synchrotron light source were used
in photoemission from thin fcc Fe films on Cu(100). The measured excha
nge splitting for the 3s and 2p levels in these films is reduced from
that measured in bulk bec Fe. For both the 2p3/2 and the 2p1/2 levels
the splittings are about half that of bulk bcc Fe. This trend is in li
ne with measurements of the 3s exchange splitting from fcc Fe compared
to bcc Fe as well. A 0.25 eV exchange splitting is observed in the 3p
core level.